CVE-2026-32953: tillitis tkeyclient · Incorrect Implementation of Authentication Algorithm
Affects tillitis tkeyclientSource CVE Database V5
Not known to be exploited · CVSS 4.7 Medium : upgrade to 1.3.0 when convenient.
Data as of 1 Nov 2026, 08:20 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.3.0
CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:H/SI:H/SA:HExploitation evidence
Disclosed: evidence found.
CVE published 20 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.
What to do
Upgrade tkeyclient and github.com/tillitis/tkeyclient to 1.3.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| tillitistkeyclient | Affected
| Fixed in
|
Gogithub.com/tillitis/tkeyclientpkg:golang/github.com/tillitis/tkeyclientOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
The primary mitigation is to upgrade the tillitis tkeyclient package to version 1.3.0 or later, where the buffer index error is fixed. For organizations unable to upgrade immediately, a practical workaround is to ensure that User Supplied Secrets (USS) do not produce a hash starting with 0x00. This can be implemented by pre-hashing candidate USS values and verifying the first byte before acceptance. Rejecting or regenerating USS values with a leading zero byte in their hash prevents the silent discard of USS and maintains key uniqueness. Additionally, organizations should audit existing USS usage to detect potential collisions or reused key material. Implementing monitoring to detect unexpected identical Compound Device Identifiers (CDIs) may help identify exploitation attempts. Finally, integrating secure coding practices and thorough testing for cryptographic modules can prevent similar buffer and flag overwrite errors in the future.
Description
CVE-2026-32953 is a medium-severity vulnerability in the tillitis tkeyclient Go package versions 1.2.0 and below. The flaw causes 1 in 256 User Supplied Secrets (USS) to be ignored silently due to a buffer index error that overwrites a boolean flag with the first byte of the USS hash. If the USS hash starts with 0x00, the USS is discarded, resulting in the same Compound Device Identifier (CDI) and key material as if no USS was provided. This undermines the authentication mechanism and key uniqueness. The issue is fixed in version 1.3.0. Until upgrading, users can mitigate risk by selecting USS values whose hash does not begin with zero.